The present invention is directed to the diagnosis and therapy of prostate cancer in men. More particularly, the invention is directed to a 3D ultrasound-guided intraoperative brachytherapy method for the diagnosis and treatment of prostate cancer.
Prostate cancer is the most commonly diagnosed malignancy in men over the age of 50, and is found at autopsy in 30% of men at the age of 50, 40% at age 60, and almost 90% at age 90. Worldwide, it is the second leading cause of death due to cancer in men, accounting for between 2.1% and 15.2% of all cancer deaths. In Canada, about 20,000 new prostate cancer cases will be diagnosed and about 4,000 men will die from this disease every year.
Symptoms due to carcinoma of the prostate are generally absent until extensive local growth or metastases develop, accounting for the fact that only 65% of patients are diagnosed with locally confined disease. Once the tumour has extended beyond the prostate, the risk of metastasis increases dramatically. Tumours smaller than 1 to 1.5 cm3 rarely broach the prostatic capsule. When diagnosed at this early stage, the disease is curable, and even at later stages treatment can be effective. Nevertheless, treatment options vary depending on the extent of the cancer, and prognosis worsens when diagnosis occurs at an advanced stage.
The prostate-specific antigen (PSA) blood test has become well established for early detection of prostate cancer, and for monitoring of prostate cancer particularly after treatment. The wide availability of the PSA test, the public""s increased awareness about prostate cancer, and the growing number of men approaching the age of 50, have all combined to increase the proportion of prostate cancer diagnosed at an early-stage. Currently, 77% of men are diagnosed to have early stage prostate cancer, compared to only 57% between 1975 and 1979. Managing and treating these increasingly early stage cancers has generated a great deal of debate in both the medical community and the public.
The standard treatment regimens for prostate cancer are: watchful waiting, radical prostatectomy, external beam radiation, and brachytherapy. While watchful waiting is appropriate for some, the majority of men diagnosed with early stage cancer will request or need treatment. There is a growing belief that aggressive therapy may not be justified for early stage disease due to the morbidity (incontinence and impotence) of radical prostatectomy. External beam radiation is effective, but requires long treatment times and results in irradiation of normal tissues. Conformal radiation therapy of the prostate may reduce this problem, however, early reports are mixed. In addition, costs are high in treating and managing patients undergoing these traditional forms of therapy.
The challenges facing physicians managing patients with possible prostate cancer are to: (a) diagnose clinically relevant cancers at a stage when they are curable, (b) stage and grade the disease accurately, (c) apply the appropriate therapy accurately to optimize destruction of cancer cells while preserving adjacent normal tissues, (d) follow patients to assess side effects and the effectiveness of the therapy. U.S. Pat. Nos. 5,562,095, 5,454,371 and 5,842,473 are directed to methods and systems for developing 3D ultrasound images which can be used for diagnosing clinically relevant cancers at curable stages and staging and grading the cancers. Hence these patents provide 3D ultrasound methods which address (a) and (b) as described above
In the past 10 years improvements in imaging technology, computer aided dosimetry, and new treatment options have stimulated investigators to search for alternative approaches such as minimally invasive therapies for localized prostate cancer, e.g., brachytherapy, cryosurgery, hyperthermia, interstitial laser photocoagulation (ILP), and photodynamic therapy (PDT). Of these techniques, brachytherapy is the most advanced and is now considered to be a definitive treatment option for early stage prostate cancer.
Minimally-invasive procedures are revolutionizing surgery and therapy, because they offer significant reductions in patient morbidity, recovery time, hospital stay, and overall cost, while preserving or increasing clinical efficacy greatly benefiting both the patient and the health-care system. Clearly, a minimally invasive procedure for prostate cancer providing these benefits is welcome, especially because of the significant morbidity currently associated with traditional therapies. Because imaging is critically important to the safe delivery of the therapy, the major imaging companies are manufacturing CT (computer tomography) and MRI (magnetic resonance imaging) scanners that allow minimally invasive procedures to be performed under direct imaging guidance. However, conventional CT does not have real-time imaging capability, and both CT and MRI are expensive technologies requiring a special facility. Ultrasound is a much cheaper and more flexible imaging modality. Unlike CT or MRI, which are often located in dedicated suites specifically built to accommodate their needs, the ultrasound machine can be moved to the operating room as needed. Moreover, with ultrasound, the surgeon or therapist sees what is happening as it occurs, in real time. As a result, percutaneous ultrasound-guided prostate therapy techniques are currently under intense investigation.
It was therefore required, to provide a safe and effective minimally-invasive method for the diagnosis and therapy of prostate cancer that would not only allow for the application of appropriate therapy but also allow the assessment of patient side effects and the effectiveness of the therapy. The method of the present invention addresses these clinical requirements utilizing the benefits of 3D ultrasound together with intraoperative brachytherapy in order to provide a superior and more accurate method of assessing, suitably treating and following-up the progression and treatment of prostate cancer than currently known traditional methods.
In the present invention, the Applicant provides a novel method and system to apply an appropriate therapy accurately to the prostate and to follow-up with patients to assess side effects and the effectiveness of the therapy using 3D ultrasound imaging. Preferably, intraoperative brachytherapy of the prostate is done using TRUS. The present invention is an extension of the Applicant""s developments in 3D ultrasound to 3D ultrasound-guided intraoperative brachytherapy.
The present invention utilizes a 3D ultrasound imaging system allowing all aspects of the procedure to be carried out intra-operatively, accurately and consistently in one session, including: semi-automated prostate margin and volume definition, real-time 3D implant guidance, verification of needle placement, and post-implant radioactive seed deposition verification. Dose planning is integrated with the present invention to allow near real-time (eg., 0.5 sec per seed) dose updates and on-line corrections of the plan based on the actual prostate implant geometry during the implantation.
In accordance with an object of the present invention there is provided a 3D ultrasound guided intraoperative method for the diagnosis and treatment of diseased tissues, the method comprising the steps of:
a pre-implant planning phase for producing a 3D tissue image comprising shape and volume of said tissue and surrounding structures and determining optimal distribution of a selected therapy;
a needle implantation phase for needle and positioning segmentation for delivery of the selected therapy to said tissue; and
a post-plan monitoring phase to verify the therapy implantation and for allowing error correction.
Preferably, the method is used to diagnose and treat prostate cancer in men however, the method can be extended to diagnose and treat several different tissues such as the liver, breast and brain.
While the method is especially beneficial to treat prostate cancer with brachytherapy, the method may also be used with other therapies such as cryosurgery, photodynamic therapy, photocoagulation and thermal therapy.
In accordance with another object of the present invention there is provided a 3D ultrasound-guided intraoperative brachytherapy method for the diagnosis and treatment of prostate cancer, said method comprising: a pre-implant planning phase for producing a 3D image of the prostate and surrounding structures and determining optimal distribution of the brachytherapy; a needle implantation phase for needle segmentation and positioning for delivery of the brachytherapy to the prostate; and a post-plan monitoring phase for verifying the needle implantation of the brachytherapy and for allowing error correction during the needle implantation phase.
In accordance with a further object of the present invention there is provided a 3D ultrasound guided intraoperative system for the diagnosis and treatment of prostate cancer, said system comprising: a 3D TRUS transducer for producing a 3D image of said prostate and surrounding structures; a first computer means for determining a needle trajectory for optimal distribution of brachytherapy; at least one needle for implanting brachytherapy to said prostate along said needle trajectory; and a second computer means for verifying implantation of said brachytherapy to said prostate.